title: Y14 positively regulates TNF-α-induced NF-κB transcriptional activity via interacting RIP1 and TRADD beyond an exon junction complex protein.
abstract: Although Y14 is known to be a component of the exon junction complex, we previously reported that Y14 regulates IL-6-induced STAT3 activation. In this study, we showed that endogenous Y14 positively regulated TNF-α-induced IL-6 expression in HeLa cells. Small interfering RNA-mediated Y14-knockdown reduced TNF-α-induced and NF-κB-mediated transcriptional activity, phosphorylation/degradation of IκBα, and nuclear localization of NF-κB/p65. As in the case of IL-6 stimuli, Y14 enhanced TNF-α-induced STAT3 phosphorylation, which is important for its nuclear retention. However, our manipulation of Y14 expression indicated that it is involved in TNF-α-induced IL-6 expression via both STAT3-dependent and -independent mechanisms. We screened signaling molecules in the TNF-α-NF-κB pathway and found that Y14 endogenously associated with receptor-interacting protein 1 (RIP1) and TNFR-associated death domain (TRADD). Overexpression of RIP1, but not TRADD, restored TNF-α-induced NF-κB activation in Y14-knockdown cells, and Y14 overexpression restored TNF-α-induced NF-κB activation in TRADD-knockdown cells, but not in RIP1-knockdown cells, indicating that Y14 lies downstream of TRADD and upstream of RIP1. Of importance, Y14 significantly enhanced the binding between RIP1 and TRADD, and this is a possible new mechanism for Y14-mediated modification of TNF-α signals. Although Y14 associates with MAGOH in the exon junction complex, Y14's actions in the TNF-α-NF-κB pathway are unlikely to require MAGOH. Therefore, Y14 positively regulates signals for TNF-α-induced IL-6 production at multiple steps beyond an exon junction complex protein.
authors.affiliation: Department of Immunology, Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan.
authors.forename: Sumihito
authors.initials: S
authors.lastname: Togi
authors.forename: Kaname
authors.initials: K
authors.lastname: Shiga
authors.forename: Ryuta
authors.initials: R
authors.lastname: Muromoto
authors.forename: Masaya
authors.initials: M
authors.lastname: Kato
authors.forename: Yuki
authors.initials: Y
authors.lastname: Souma
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Sekine
authors.forename: Shigeyuki
authors.initials: S
authors.lastname: Kon
authors.forename: Kenji
authors.initials: K
authors.lastname: Oritani
authors.forename: Tadashi
authors.initials: T
authors.lastname: Matsuda
mesh_terms: D045744:Cell Line, Tumor; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D020672:I-kappa B Proteins / Q000378:metabolism; D015850:Interleukin-6 / Q000096:biosynthesis / Q000235:genetics; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism*; D028861:Nuclear Pore Complex Proteins / Q000235:genetics / Q000378:metabolism*; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D011401:Promoter Regions, Genetic; D034622:RNA Interference; D034741:RNA, Small Interfering; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D050794:STAT1 Transcription Factor; D050796:STAT3 Transcription Factor / Q000235:genetics / Q000378:metabolism; D053199:TNF Receptor-Associated Death Domain Protein / Q000235:genetics / Q000378:metabolism*; D047992:TNF Receptor-Associated Factor 2 / Q000235:genetics; D051996:Transcription Factor RelA / Q000378:metabolism; D014158:Transcription, Genetic; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*
chemical_list: C119724:AGFG1 protein, human; D020672:I-kappa B Proteins; D015850:Interleukin-6; C491494:MAGOH protein, human; D016328:NF-kappa B; C000606204:NFKBIA protein, human; D028861:Nuclear Pore Complex Proteins; D009687:Nuclear Proteins; C406243:RBM8A protein, human; D034741:RNA, Small Interfering; D016601:RNA-Binding Proteins; D050794:STAT1 Transcription Factor; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; D053199:TNF Receptor-Associated Death Domain Protein; D047992:TNF Receptor-Associated Factor 2; D051996:Transcription Factor RelA; D014409:Tumor Necrosis Factor-alpha; D000072000:NF-KappaB Inhibitor alpha